Ground speed indicator



Jan. 20, 1948. F. F. HAUPTMAN GROUND SPEEDy INDICATOR Filed July 28, 1945 elsheets-sheet 1 JNVENTOR.

flEDEre/C- FHA UPr/v/A N.

ATTORNEY.

Jan.. 2o, 1948.

F. F. HAUPTMAN GROUND SPEED INDICATOR Filed July 28, 1945 6 Sheets-Sheet 3 R. feeogE/c f.' HAuPrMA/v.

ATTORNEK Jan. 20; 1948.V F, F HAUPTMAN A 2,434,694

GROUND sPEEn` INDICATOR Filed July 28, 1945 6 Sheets-Sheet 4 INVENTR. l FkEDER/c RHAUPTMAM BY' 'wf-f M f ATTORNEK D 101 J To ECHO/warme Jan. 20, 1948. 'F. F. HAUPTMAN 2,434,694

- GROUND SPEED INDICATOR Filed July 28, 1945 6 Sheets-Sheet 5 IN V EN TOR.

ATTORNEY.

FEEDER/c FHA upv-MAN.

Jan. 20, 1948. F. F. HAUPTMAN 2,434,694

GROUND SPEED INDICATOR 6 Sheets-Sheet 6 Filed July 28,' 1945 INVENTOR. FEEDER/c FHA uPTMA/v.

ATToRA/EK Patented Jan. 20, 1948 UNI PAT E N T @3F Fl EL GROUNDfiS'PEED INDICATGRf` Frederic F. Hauptinan, Rego Park,'N. Y., assigner' t'o Square D'Cm'pany, Detroit; Mich., al cor= poration" of VYMichigan Application July 28; 1945, Serial No. 607,511f

1l This r invention.. relates to` an-L instrumentfor determining the speed` of -an aircraft-relative to .a

datum point; more partioularlf aircraft speedrelative to the ground.

@he object offtl'e inventionis aninstrument which williprovid. a directaccurate reading, of the aircraft ground'speedwithoutrequiringvisual sighting. or computation.' the-observer,

Ahotherobjeot ofthe inventionis'the provision of.. an. aircraft ground` speed! indicator. operating, froml the. radio. lc'iroadast"Y of a station, 4.the barometricpressureof whiclisllnown.-

Another object" of .thel invention is .an aircraft instrument which will. properly compound. the values 'oi" altitude above a datumf pointgangular velocity.- about the datum point 'and"`angl. of'tilt to the datum p oint-` tol providea directl reading oil'the groundl'speedoflthe aircraft.

Another o'lcjectI of "the invention is`A an- .aircraft groundspeedindioator operatinggfrom the radio broa'dasty of"a station' of :known .barometrio .pressure whichl Willproperly compound! ythe values -of altitude L above.- the station."- and.. of.' the angular ve1ocity; ahd`ang1e' of tilt of directional .antenna loops directedattleV station to provide a direct reading.. of the groundspeedmof the aircraft.

Other objectsv and'fature'stthe invention will be readily, apparent" to thoseskilled inthe` art from the specioation and' appended drawings illustrating certain. preferred" embodiments in which: Y

Figurelfis. a front'elvatinal'viw of..a ground speed. indiator.; accordi'igetowthe. present.; invention..

Figure 2ll`is` a transversesectional view on the line II-II'of Figure 3."

Figure is. a`sectio'na1 view on theline's IlI-II'I' offEi'gurel'.

Figure 4 isa rearelevationalfview of .theinstrument.`

Eigure'is aside-.elevational lview-ofl the instrumente Figure 6"is asectinal view on the linesIVL-IV of Ei'gure 4'.

Figure .7 is apartial schematic" representation of the directionalantennalops andtheiroperating mechanism. Y

Figureisa detaldview ofloperatigeparts fontle.diectlonallloopse Figure 9is. as.schematicrepfresentation. of the relation. of.` the-. aircraft .5to the radio broadcast station .tn whieh`A its-.dirlectionalloops are directed.

f The Ainstiunrientshown inFgures 1 through .6 comprises@a-.casing-u I closed atv the front by a transparentlglss. .windows Z'Lmaintainedin' place 15` Claims. (CL Z50-11) by a snap ring 32' At" the fear'. of easing I are' mounted three conditionlresponsive units, a' drag cup tachometer unit* LI; a` selfsynchron'ous receiver unit 5, and Van altitude pressure responsive unit. *A

The altitude pressure responsive" unit 6`comprises -a casing. 'I mounted to the casing I in airtight relation through the"sealing.'ring'8L- Within the casing- I isa support"Sniountedupona'rotate able; ring Ygear I i. On the support by' meansof rod I2',V are mounted tlir'eeseriallyconnected aneroid. capsules I3' to which" areconnecteda link Irlth'rough acompensatingunit' I5: Thelink I4 is pivotally connected't'o' theendof anarm' I6 mounted on a rocksliaftI T.' Also' mounted on the roclishaft il loyjarrrii Ian'o'llinkv Ifisa counter' weight element 2'I. Upon the"rookshaif` I'I`V is mounted a gear.' sector2f2"meshing"witha pinion 23 yto which is connectedagearwheel 24 meshing with pinion' 25` mounted' onA` shaft 26.A` A light spiral springzl biases 'th'egeary and-pinion `23 toitak'e up`v any backlash in 'the" gearing parts:

Upon the end'of shaft'ZSsfmounteda rotatable magnetic elementi28;'wliicl'drives al secondlmagnetio'eleinent 29mountedtupori-shait'- 311i Between" the magnetic elements 2`8and 29 tisa-inonmagnetic' cup.' 32 mounted to'oasing" I-` in airtight relation through thesealin'gg'asket, the Triage netio drive element'; magnetic "fol1ower29 and cup 32"'b'eing"provide'dto insure"an" airtight' Vseal for" the casing I within *which* the aneroid "cap-v sules I3" are disposed. The casing1"is" adapted to be connected in usual mannerk to'thej static openingY of' a Pitot-statie`tube' through the Arear casing.' opening '34. Upon'the'shaft 31 `isrnounted a gear 35 "meshing" with" a gear`3'llmountedup'on aL holIWshaft V3'! on the forward elid- 0f which is mounted a'rotatable "annular 'dial 38 'calibrated in units of ground'speed'asl'show'nin Figurel.'

Within the easings 'I andi is rotatably-mounted a shaft '39' having` a manualknob 'IH accessible at thefr'ontoftheinstrument.' Upon the shaft 39 is with a. rotatable shaft 5I carrying a permanent magnet 52 about which is disposed the cup shaped element 53 of conducting material mounted upon a shaft 54. Rigid with the shaft 54 is a logarithmic gear sector 55 meshing with a pinion 56 eccentrically mounted on a shaft 51. with the shaft 51 is a gear wheel 58 meshing With the gear 59 mounted on a shaft 6I. The shaft 6I has a reduced portion 62 which extends through the hollow shaft 81 and forms a staff supporting a pointer 63.

The shaft 51 has a reduced portion 64 upon which is rotatably mounted a hub 65. A spiral spring 66 has one end connected to the hub 65 and its opposite end mounted upon a pin 61 carried by the gear 58. Rigid on the hub 65 is a pinion 68 mounted eccentrically of the axis of the hub and meshing with a logarithmic gear sector 69. The sector 69 is carried by shaft 1I of the self-synchronous receiver 5. The details of the construction of the self-synchronous receiver form no part of the present invention but it is provided with the usual stationary core 12 and stationary windings 13 and with the rotor magnet 14 and Winding 15 mounted on the shaft 1I.

Thedirectional antenna loops of the aircraft and their operating mechanism shown in Figures 7 and 8 comprise the loops 16 and 11, the loop 16 being rotatable about a vertical axis and the loop 11 about both the vertical and horizontal axes. The loop 16 is supported upon a shaft 18 carrying a gear 19 meshing with a pinion 8|. The pinion 8| is connected to a gear S2 meshing with a pinion 83 on the shaft of a motor 84, Also meshing with the pinion 83 is a gear 85 connected to a pinion 86 meshing with a gear 81 on a shaft 88 carrying a cradle 69 in the trunnions of which the loop 11 is pivotally mounted for rotation about its transverse axis. At one side of the cradle 89 is provided a motorr 9I which through suitable gearing indicated at 92 effects the tilting of the loop 11. At the opposite side of the cradle 89 there is disposed a lever 93, shown more clearly in Figure 8, having a slo-t 94 in which is located a rectangular element 95 rigidly disposed on the mounting shaft of the loop 11 and rotatable therewith. The end of the lever 93 is pivotally connected at 96 to a rack 91 which carries a slotted guide 98 and which meshes with a pinion 99 mounted on the shaft of a self-synchronous transmitter IUI.

In the schematic representation of Figure 9 there is indicated a radio barograph comprising a pressure responsive element I92 and a broadcast antenna |63. This radio barograph may be automatic in operation, sending forth an identiable signal indicating the barometric pressure at the station or the broadcast may be an oral recitation of the pressure value, All that is required is that the aircraft operator know the value of the barometric pressure at the station and that the broadcast be in operation so that his automatic radio compass units can be tuned.

The automatic radio compass is a standard item whose detailed construction forms no part of the present invention and it has been considered unnecessary to describe this conventional element herein. However, it wil1 be understood that two such automatic radio Compasses are utilized, one of which is responsive to the loop 16 and effects rotation of the motor 84 to maintain the plane of the loop at right angles to the vertical plane through the broadcasting station. A second automatic radio compass unit is connected Rigid to the loop 11 and operates the motor 9| to maintain the plane of the loop 11 at right angles to the line to the broadcasting station. The selfsynchronous transmitter IBI is connected by wiring, not shown, in conventional manner to the self-synchronous receiver 5. The shaft of motor 84 is connected through a flexible drive cable I04 to the drag cup tachometer unit 4.

In Figure 9 the height of the plane above the broadcasting station has been indicated by the symbol h, the tilt angle of the loop 11 is represented by the symbol a, and the angular velocity of loops 16 and 11 about a vertical axis is indicatedby the symbol n. The ground speed of the aircraft is the product of the angular velocity n, the altitude h, and the co-tangent of the tilt angle a, The logarithm of the ground speed will be the sum of logarithm n plus logarithm h plus logarithm co-tangent a. The instrument, according to the present invention, adds these logarithmic values so that the ground speed is directly indicated upon the logarithmic scale of dial 38.

As the motor 84 rotates to rotate the loops 16 and 11 about a vertical axis in the travel of the aircraft, the rotor 52 of the drag cup tachometer 4 will be rotated to apply a torque to the cup 53. This effects rotation of shaft 54 and of logarithmic sector 56 to rotate pinion 56 and shaft 51 against the bias of the spring 66. In view of the logarithmic curve form of the gear teeth of the sector 55 meshing with the eccentric pinion 56, the logarithmic value of the angular velocity n will be applied to the shaft 51 and to the gear 58 mounted thereon.

As the` loop 11 istilted to maintain its plane perpendicular to the line to the broadcasting station, the self-synchronous transmitter IUI will be moved, through the lever 93 and the rectangular element sliding in the slot 94 thereof, proportional to the co-tangent of the tilt angle a. The rotation of the rotatable element of the selfsynchronous transmitter Il is reflected in a corresponding rotation of the rotor 14 and shaft 1I of the self-synchronous receiver 5. Rotation of the shaft 1| rotates Vlogarithmic sector 69 to rotate pinion 68 and hub 65 to vary the tension on spring 66. Since the gear teeth of the sector 69 are inthe form of a logarithmic curve, the rotation of the hub 65 will correspond to the logarithm of the co-tangent of the angle a. Since the spring 66 is connected to the gear 58, the amount of rotation of the gear 58 effected by the torque on the drag cup 53 will be determined not only by the speed of rotation of the tachometer shaft 5I but also by the position of the rotor shaft 1I of the self-synchronous receiver 5. Accordingly, in the rotation of the gear 58, the instrument has added the logarithm of the angular velocity n to the logarithm of the co-tangentY of the tilt angle a. Rotation of the gear wheel 58 rotates gear 59 to rotate shaft 6I and the reduced portion 62 thereof to rotate pointer 63. Hence, the rotation of pointer 63 represents the sum of the logarithms of the angular velocity and the co-tangent of the tilt angle.

By manipulating the knob 4 l, the operator sets into the instrument the altitude pressure of the broadcasting station. Rotation of the knob through pinion 42 effects rotation of the gear Wheel II to bodily rotate the altitude responsive elements. The adjusted position is determined by the reading on the dial 48 at the index 49. With the instrument set to the station altitude pressure, thef'altitude of the plane above the station alamo;

'will -be reflected fin an expansion V'of the die phragm capsules l 3 to move link `,lll androtate shaft l1 to rotate the sector 522. Sector `22rotates pinion 23 and gear'24 connected theretoto rotate pinioni25,sha'ft 26, and magnetic driver 28. The magnetic element 29 follows-the movement ofthe driver 28 to rotate shaft' 3l andgear 35- which in turn rotates gear `36fandhollow shaft 31. The annular scale 38 is mountedon the shaft '31 and rotates therewith. As thealtitude-altitude pressure relation is logarithmic, the `angular movement of the annular dial 38 bythe calibrated altitude 'pressure responsive mechanism-will be logarithmic with respect to the altitude' difference. The angular movement of the `dia-'l 38 :adds .tothe angularv movement of the pointer 63 so as tocado the-logarithm of'the altitude difference to the logarithme of the angular velocity and tilt angle to effect the desired rreadingof the ground speed on thelogarithmic scale of the dial 38 opposite 'thepointer 63.

"In the operation of the instrumenuthe operator, 'to-'secure a direct readingsets the :broadcasting -station altitude pressure by rotating'the dial 8 to, as `many variations `will be readily apparent lto those skilled in the artandV the invention isto be given its broadest possible `interpretation withinthe terms of the following claims.

What is claimed is:

.1. .A ground speed indicator foriaircraft com prising means responsivesto 'the altitude fof the aircraft above adatumpolint, means responsive to the Vangular velocity of Athe Vaircraft 4about the datum 'po/init, means responsive'to the tilt angle of :a line from/the aircraft'to the datum point, "a dial calibrated in. units ofv ground speed; a referencewith respect to whichfsaiddialis read,vand meansfor effecting relativefmovement between said dial andref-eren-ce vinifacc'ordarice `with the Vresponse of'said' three responsive means to indicate' by `theposition .of the reference relative-.to the .indicia `on the. dial theaground speed or the aircraft.

,2. In a `"ground speed indicator for aircraft, means movable `proporltionately"to `the diierence in altitude.pi-esame between said aircraft and .a

:datum npoint,` means movable proportionately'to .the logarithmof the angular velocity of therein craft about thedatumpoint, means movablepro- Vportionat'ely to the logarithm.oftheioos'tangent .of the tilt angle 'of :a .lineLfrcm :the aircraft :to the datum point, azdial.havingalogarithmic vscale of indicia :of ground speed, a reference withirespect to "which said dial 'is read, fandmeans. for .cor-

:zrelating themovementfoi said movablefmeans to effect relative movement between `saidxriialand .i

reference to `indicate by the positionsof .the .ref-

erience relative to thef'dial indicia the/ground speed of the aircraft.

3. .lin a Yground `speed indicatorlfor aircraft,

means `movable proportionately to the difieren-.ce `in valtitude pressure between the aircraft yandan.

datum point, means movable proportionatelyto the logarithm of the angular Velocity of the aircraft aboutthe datum ponhmeans movable proportionately to the logarithm of the co-tangent Aoftheftiltaangle of a line frcmthe aircraft to the datumpointffa dial having a logarithmic scale oiindi'cia'o'f ground speed, a reference withcrejjspect `to which said dial is read, and means-for eiecting relative movement between said dial and yreference throughcadistance equal to the sum ofthe movements of said movable means to indi- "cateby theposition of the reference relative to "the indiciaonthe dialthe ground speed of the aircraft.

.4. V2in a ground speed indicator for aircraft, meansmovable proportionately to the logarithm f-oi' thediierence in altitude between the aircraft and a datum point, means movable proportion- .atelytotheiogarithmof the angular velocity of thezaircraftsabout the datum point, meansirnovicraftito thezdatum'point, `a dial having a logarthmicvscaleofindicia ofground speed, areference with4 respectV t'o'which'said dial is read, and

means for eifectingrrelative 'movement between saidfdialand reference for a distance equal to the sum 'of the'movements 'of said movable means ltcfindic'ate by the position of the reference relative Ltoztheindi'cia Ion the dial the ground speed ofthe aircraft.

5. In a ground speedindicator for aircraft, `a rotatable .dial carrying indicia of units of ground speed, :afrotatable pointer movable across said dial. andwithrespect to which the ground speed indiciaisgread; means responsive to the altitude :of Jtheaircraitabovo a vdatum point, means re- .ff'sponsive to the angular velocity about the datum point.. means responsive to the tilt angle of a line Vfrom theaircraft to the-datum'point, and means for rotating said dial and pointerso thatcthe sum of theirfmovements is the sum of `the movements of saidresponsive means to indicate by the position relative to Vtlfledial the ground speed of the aircraft.

6. .In aground speed indicator for aircraft, a vrotatable dial carrying indicia of units of ground speed, a rotatable pointer movable across said dial andwith respect to which the ground speed indicia is read, means for rotating said dial .through Van angle proportional to the difference y co :inalt'tude pressure .between the aircraft and a Vfabout'thie datum point and the logarithm ofthe 42o-,tangent Iof the tilt angle of a line from the aircraft .to-thedatum lpoint whereby the position of the pointer relative to the indicia on the dial will indicate theground speed of the aircraft.

.7.In-a grou-nd speed indicator for aircraft, a rotatabledial carrying indicia of units of ground speed,` arotatable pointer movable acrosssaid dial andvvith respect to which the ground speed inis read, means `for rotating said dial through .an angleproportional to the diierence `in altitudegplfessu'e between the aircraft and a ground broadcast station, directional means tuned for direction toward the broadcast Astation in the l`tiraveloof the'aircraft, and means for-rotating ysaid pointer. through .an angle proportional to the vsumcoi thceiogarlthm :of the .angular 'velocity of v thewdirccticnal meansabout a vertical axis and 'the logarithm-.foi the `co-tangent vof the tilt Vangle oi-thezdireotionai means whereby to indicate `by a ground radio station of known altitude pressure, directional means tuned for direction toward the station in the travel of the aircraft, means responsive to the altitude pressure of the aircraft, means for adjusting said responsive means to the known altitude pressure of the broadcast station, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means correlating the movements of said responsive means and of said directional means to effect relative movement between said dial and reference to indicate by the position'of the reference relative to the indicia on the dial the ground speed of the aircraft.

9. An instrument for determining the ground speed of an aircraft from the broadcast beam of a radio station comprising means responsive to the difference in altitude between said aircraft and broadcast station, means responsive to the angular velociti7 of the aircraft about the broadcast station, means responsive to the tilt angle of a line from the aircraft to the broadcast station, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said dial and reference in accordance with the response of said responsive means to indicate the ground speed of the aircraft.

10. In an instrument for determining the ground speed of an aircraft from the broadcast beam of a radio station, directional means tuned for direction toward the station in the travel of the aircraft, means responsive to the difference in altitude between said aircraft and broadcast station, means responsive to the angular velocit?)7 of the directional means about a Vertical axis in the travel of the aircraft, means responsive to the tilt angle of the directional means, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between saiddial and reference in accordance with the response of said responsive means to indicate the ground speed of the aircraft.

11. In an instrument for determining the ground speed of an aircraft from the broadcast beam of a ground radio station, means for setting in the instrument the altitude pressure at the broadcast station, directional means tuned for direction toward the station in the travel of the aircraft, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said dial and reference proportionately to the sum of the logarithms of the altitude difference between the aircraft and broadcast station, the angular Velocity of the directional means about a vertical axis, and the cotangent of the tilt angle of the directional means.

12. In an instrument for determining the ground speed of an aircraft from the broadcast beam of a ground radio station, means for setting in the instrument the altitude pressure at the broadcast station, directional means comprising radio antenna loops tuned for direction toward the station in the travel of the aircraft, means responsive to the difference in altitude between said aircraft and broadcast station, means responsive to the angular velocity of the directional loop in the travel of the aircraft, means responsive to the tilt angle of the directional loop, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said dial and reference in accordance beam of aground radio station, means for setting in the instrument the altitude pressure at the broadcast station, directional means comprising radio antenna loops tuned for direction toward the station in the travel of the aircraft, means movable proportionately to the difference in altitude pressure between said aircraft and broadcast station, means movable proportionately to the logarithm of the angular velocity of the directional loop about a vertical axis inthe travel of the aircraft, means movable proportionately to the logarithm of the co-tangent of the tilt angle of the directional loop, a dial having a logarithmic scale of indicia of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said dial and reference through a distance equal to the sum of the movements of said movable means toindicate by the position of the reference relative to the indicia on the dial the ground speed of the aircraft. i

14. In an instrument for determining the ground speed of an aircraft from the broadcast beam of aground radio station, means responsive to the altitude pressure of the aircraft, means for adjusting said responsive means to the altitude pressure of the broadcast station so that the movement thereof is a function of the difference in altitude pressure between the aircraft and the broadcast station, directional means tuned for direction toward the station in the travel of the aircraft, means exerting a torque whose value is determined by the angular velocity of the directional means about a vertical axis in the travel of the aircraft, responsive means movable by said v torque against a spring bias, positional means determining the value of said spring bias in response to variation in the tilt angle of said directional means, a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said dial and reference in accordance with the movement of said responsive means to indicate the ground speed of the aircraft.

15. In an instrument for determining the ground speed of an aircraft from the broadcast beam of a ground radio station, means responsive to the altitude pressure of the aircraft, means for adjusting said responsive means to the altitude pressure of the broadcast station so that movement thereof` is a function of the difference of altitudev pressure between the aircraft and the broadcast station, directional means tuned for direction toward the station in the travel of the aircraft, means exerting a torque whose value is proportional to the logarithm of the angular velocity of the directional means about a vertical axis, responsive means movable by said torque against a spring bias, positional means determining the value of said spring bias in accordance with the logarithm of the co-tangent of the tilt angle of said directional means. a dial calibrated in units of ground speed, a reference with respect to which said dial is read, and means for effecting relative movement between said diall and reference in accordance with the movement of said responsive means to indicate the ground speed of the aircraft. Y

FREDERIC F. HAUPTMAN. 

